The aim of this project is to characterize schistosome surface molecules relevant to immunity, to analyze the genome of the parasite in relation to specific biological properties of the organism and to clone important schistosome immunogens. A. Development of a paramyosin BCG recombinant cDNA's encoding paramyosin were cloned into BCG for vacome testing. B. Genetic analysis of natural schistosome populations. Using a rDNA probe, the genetic heterogeneity and geographic variation of a collection of S> mansoni isolates from Brazil was characterized. C. Creation of an expression clone bank for T epitope screening. A battery of 500 clones from a S. mansoni expression cDNA were selected for use in identifying important antigens recognized by T cells from vaccinated animals.